The conventional power conversion devices fall into two categories, i.e. the electric motor and the internal combustion engine. However, the former requires electric power for operation which is high in cost thereby making it unfit for practical use, while the latter uses the combustion of gasoline or diesel to generate power which will inevitably be accompanied with noise and air pollution.
Therefore, it is an object of the present invention to provide a hydraulic power conversion device which can obviate and mitigate the above-mentioned drawbacks.